Critical Appraisal of Antimicrobials for Prevention of Infections in Immunocompromised Hosts

[Use of antimicrobials in acute canine diarrhea - overview of potential risks, indications and alternatives]

In Germany, antibiotics are frequently used in dogs with gastrointestinal disorders such as acute diarrhea. In line with global efforts to limit antibiotic use, this literature review aims to provide a guideline for the rational and judicious use of antibiotics in acute canine diarrhea. Antibiotics can lead to gastrointestinal side effects and may exert a negative influence on the intestinal microbiota in addition to increasing the occurrence of resistant bacteria. There is also evidence that chronic immunological diseases may be triggered by the administration of antibiotics. Therefore, these should not be administered in uncomplicated acute diarrhea without signs of sepsis or systemic inflammatory reaction. In addition, enteropathogenic bacteria usually do not play a role in the etiology of acute diarrhea. For select clinical entities such as acute hemorrhagic diarrhea syndrome, antibiotic therapy should only be recommended in cases displaying signs of bacterial translocation with subsequent sepsis. In the case of parvovirosis, on the other hand, the administration of antibiotics is unavoidable due to the immunological incompetence of the dog caused by the accompanying severe neutropenia.

Antibiotic prophylaxis in children with cancer or who have undergone hematopoietic cell transplantation

Bacterial infections are common in children with cancer and can lead to life-threatening complications. Infections in these patients mainly occur during neutropenic periods, and may be caused by Gram-positive or Gram-negative bacteria. The patients at highest risk of serious infections include those with acute lymphoblastic leukemia (ALL) or acute myeloid leukemia (AML), and those undergoing myeloablative hematopoietic cell transplantation (HCT). This is a review with the main aim of making a critical appraisal of the literature, and summarising what is currently known and can be recommended. The most significant studies support the use of floroquinolones (mainly ciprofloxacin) as the most rational approach to treat pediatric patients with probably long-lasting neutropenia, although trimetoprim-sulphametoxazole and amoxicillin/clavulanate may theoretically be valid alternatives. No prophylaxis seems to be needed for children with cancer without severe neutropenia. However, a global evaluation of the studies of antibiotic prophylaxis in children with cancer indicates that there are not enough data to prepare definite guidelines for its use or avoidance in pediatric oncology, and so further studies are needed. It is not only important to define the best antibiotic regimens for the children in whom such prophylaxis is useful, but also to identify precisely those who do not need it. This would avoid the antibiotic misuse that probably occurs at the moment because many low-risk children with cancer are treated. As prophylaxis against infections requires long-term adherence to an antibiotic regimen, the attitudes and beliefs of stakeholders need to be fully considered.

Antibacterial prophylaxis in neutropenic children with cancer

During the period of neutropenia induced by chemotherapy, patients have a high risk of infection. The use of antibiotic prophylaxis to reduce neutropenia-related complications in patients with cancer is still disputed. Recent meta-analysis and clinical trials demonstrated that antibiotic prophylaxis with quinolones reduces febrile episodes, bacterial infections and mortality in adult oncological patients with neutropenia induced by chemotherapy in acute leukaemia. In paediatric patients, the only randomized, double-blind, prospective study until now suggests that amoxicillin/clavulanate may represent an effective prophylactic treatment in reducing fever and infections in oncological children with neutropenia, with an efficacy that is statistically demonstrated only in patients with acute leukaemia. Considering the risk of resistances, antibiotic-prophylaxis should be used only in selected patients.

Antibacterial prophylaxis in neutropenic patients

Antibiotic prophylaxis has been used for several decades to prevent infection in chemotherapy-induced neutropenia and its benefits have been debated just as long. Recent analysis suggests that quinolones may actually be life saving in high-risk groups such as acute leukaemia and autologous bone marrow transplant but these benefits are likely to be negated in the long term by the development of quinolone resistance.

Sepsis

OBJECTIVES

To review infection and sepsis in patients with cancer and to provide an overview of controversies and research-based practices of infectious complications and management strategies.

DATA SOURCES

Research studies, review articles, web sites, and consensus documents.

CONCLUSIONS

Traditional assumptions about infection and its optimal management are redefined by research regarding transfusion and catheter-related infections, prophylactic antibiotic administration, use of growth factors, and antimicrobial therapy regimens.

IMPLICATIONS FOR NURSING PRACTICE

Infection is still the most common source of morbidity and mortality among cancer patients. The importance of recognizing high-risk patients, implementing infection prevention practices, and prompt intervention for infection symptoms has been established.

Reflections on gut decontamination in hematology

In Europe, but decontamination (GD) is largely used in the prophylaxis of bacterial infections in departments of oncohematology treating neutropenic patients, in particular those patients subject to profound (absolute neutrophil count (ANC) <100/mm3) and prolonged (>10 days) neutropenia, such as patients undergoing bone marrow allografting or induction chemotherapy for acute leukemia. Initially, treatment was in the form of non-absorbable antibiotics, but this has been partially superseded by quinolone-containing regimens, in particular in the centers participating in EORTC trials. In the last two EORTC trials comparing different regimens for the treatment of febrile neutropenia, 57-73% of the patients were receiving GD. A French epidemiologic study, performed prospectively and consecutively in 36 oncohematology centers, has recently shown that 45% of febrile neutropenic patients receive digestive decontamination (DD) at the onset of their first febrile episode. The value of GD has been the subject of much controversy. Numerous trials, some of which were controlled, were performed in neutropenic patients in the 1980s, prior to trials of GD in intensive care units, but did not lead to a consensus in the medical community of the value of GD. Moreover, GD is not, or is infrequently, used in the USA. Apart from trials involving the quinolones, very few studies have been published during the last 10 years. Despite this, policies have not changed greatly in the various centers. The CLIOH group has gathered the opinions of experts invited to a multidisciplinary meeting that took place in Paris in October 1996. The text that follows summarizes the reflections arising from this forum. It should be noted that this meeting was not designed to be a consensus conference, but rather to re-examine the correlation between the data in the literature and actual clinical practice and to highlight the main problems posed by DD in current oncohematology. The experts were separated into three working groups, each of which has drafted a report which appears in the text below.

Epidemiology of infectious complications in cancer patients

Patients with underlying malignancies are at risk for a wide array of infectious diseases that cause significant morbidity and mortality. To develop a clear etiologic understanding of the infectious agents involved first requires a knowledge of the factors that predispose to infection. Neutropenia is clearly the single most important risk factor for infection in the cancer patient. However, a variety of both host and treatment-associated factors act together to predispose these patients to opportunistic infections. Approaching the individual malignancies with a knowledge of the underlying risk factors helps logically guide diagnosis and therapy. The astute clinician must also be aware of new and emerging infections in this patient population. As new pathogens are discovered and established pathogens become increasingly drug resistant, they will continue to present challenges for physicians caring for these patients in the years ahead.

Prevention of infection in immunocompromised hosts

The prevention of infection in patients with cancer has changed tremendously over the last decade, but remains in evolution. Despite many clinical trials examining the role of antibacterial, antifungal, and antiviral prophylaxis, there is still discussion among physicians about not only which patients require prophylaxis, but also the optimal regimen. Nevertheless, many of these regimens offer the hope to prevent infection in patients with underlying neoplastic diseases. There is no therapy that is uniformly effective in all settings. This is generally due to the severity of the defects in host defenses and the virulence of the microorganism. Hopefully, the future will hold many new therapeutic options to help prevent infection in patients with cancer.

Prevention of infections in bone marrow transplant recipients

Bone marrow transplantation (BMT) is increasingly used in the treatment of hematologic malignancies, solid tumors, and congenital diseases. The number of patients receiving a BMT increased from approximately 5000 in 1989 to 12,000 in 1995. Infectious complications are the most common cause of morbidity and mortality in the peritransplant period in patients undergoing autologous BMT. Additionally, infectious complications are a serious cause of complications in recipients of matched sibling allogeneic BMT, unrelated BMT, and related mismatched BMT.